Underground water-management system for mines

ABSTRACT

The invention relates to an underground liquid-management system for mines for generating and/or storing energy, for storing and/or cleaning liquids located in the mine, comprising: at least one first store, which is formed by a cavity of the mine, at least one second store, the bottom of which is arranged above the bottom of the first store, at least one line connecting the stores in order to conduct the liquid, at least one pumping device for conveying the liquid through the lines from the first store into the second store, and a geothermal device at least for operating the pump.

The invention relates to an underground liquid management system for mines, a waterworks comprising the liquid management system and an output system and a method for operating a liquid management system.

South Africa, South and Central America and various other countries and regions of the world, for example, have mines or pits which are disused or still in operation and which in some cases reach to very great depths (e.g. 2000 to 5000 m). These mines and pits contain cavities at different levels. The cavities can in part already be filled naturally with water.

DE 103 61 590 A1 discloses a pump storage station, in which a cavity which is artificially created at least for the lower basin is used in a shaft installation.

DE 195 13 817 B4 describes a pump storage station which is disposed in a pit of an existing or cleared open pit mine of a brown coal deposit. The depth of the aforementioned pit is utilised in order to provide the storage basins, which are required for the pump storage station, with a corresponding height difference with respect to each other. At least the lower basin is disposed below the level of the surrounding area. The artificially constructed stores can be constructed by the excavated material which occurs during extraction of the brown coal deposit.

It is known from DE 100 28 41 to provide a hydroelectric power station as a block-like structural unit having a cylindrical basic shape which is located on the ground surface or is completely or partially embedded into the ground, in order to make hydro power useful in an artificial manner irrespective of natural ground topographies and natural water potentials. Two stores disposed one above the other are provided in the artificially constructed, closed structure. In a storage operation, water is pumped by means of a pump from the lower store into the upper store. In an energy generation operation, the water is guided back from the upper store into the lower store by a turbine, which is disposed between the stores, for electricity generation. The energy required for the pump can be provided by means of wind or solar energy plants or a geothermal unit.

The prior art thus demonstrates pump storage stations which are provided merely for energy generation, wherein the storage basins are provided for the most part artificially and separately in the ground. Only DE 103 61 590 A1 proposes producing a lower basin of a pump storage station from an artificially created shaft installation.

Therefore, it is an object of the present invention to provide a system which in a simple and cost-effective manner provides for comprehensive liquid management (e.g. water management) and is used not only for generating and storing energy but also for storing and cleaning liquids located in a mine.

This object is achieved by the subject matter of the independent claims. The dependent claims develop the central idea of the invention in a particularly advantageous manner.

In accordance with a first aspect, an underground liquid management system for mines is provided for generating and/or storing energy, storing and/or cleaning liquids (e.g. water and/or surface waters) located in the mine or its natural surrounding area;

thus also comprising the reduction or removal of pollutants (inter alia also of solids) from liquids from the natural surrounding area. The term “liquid” is thus understood hereinafter to mean any liquid which passes naturally or artificially into the cavities of the mine or is located in the natural surrounding area of the mine, in particular groundwater or surface water (e.g. rainwater). The system has at least one first store which is formed by a cavity of the mine, and at least one second store. At least the bottom of the second store is disposed above that of the first store. In a particularly preferable manner, the second store is disposed above the first store. The underground liquid management system also comprises: at least one line, which connects the stores, for conducting the liquid, at least one pumping device for conveying the liquid through the lines from the first store into the second store, and a geothermal device for generating geothermal energy at least for operating the pump and preferably also for operating further components of the system, i.e., for the auxiliary power of the system, and optionally also for provision to third parties, that is e.g. by feeding the generated energy into an electricity network (electrical energy) or into a heat store (heat energy). The geothermal device can also be provided for generating heat or cooling energy, in order to utilise this e.g. for surrounding residential or industrial areas or in the mine itself; e.g. as a thermal power station/heat pump or energy system.

The system in accordance with the invention thus renders it possible in a simple and cost-effective manner to utilise already existing cavities of a mine without undertaking any further significant reconstruction measures for comprehensive liquid management (storing and/or cleaning liquids and solids and/or (simultaneously) generating and/or storing energy). The liquid management includes e.g. the return of the system to its natural state, i.e., the renaturation of the mine and/or the liquids, in particular the groundwater and surface water. The liquid management also includes the reduction of contaminants both in the water (groundwater and surface water) and also in the mine, i.e., the geological layers themselves. Furthermore, comprehensive groundwater protection thus also takes place, since the naturally present groundwater of a specific geological layer in the mine is cleaned and in particular not polluted further. In synergy with the environmentally sound system, the geothermal energy, i.e., ground heat, which can be accessed particularly effectively in mines owing to the depth thereof can be utilised for generating electrical energy and optionally also for generating heat and/or cooling energy; in particular for the operation of the pump of the liquid management system or the mine per se. Furthermore, generating energy from geothermal energy can reduce the mine operator's dependence upon external energy suppliers (e.g. for electricity, heat, cooling energy, . . . ), whilst at the same time at least this part of the energy supply takes place with sustainable (regenerative) energy.

Preferably, all or at least a large proportion of the stores to be used for the underground fluid management system are formed by cavities of the mine. In this manner, the additional provision of external tanks is no longer required and the provision of the liquid management system is simplified considerably and is cost-effective and simple to produce.

Preferably, cleaning stages are provided between and/or in the stores. In this manner, contaminated liquids can be cleaned in an environmentally sound manner and even in the system itself This leads to an effective and efficient reduction of contamination in all waters located in the mine, in particular to marked groundwater protection which also has a positive effect upon renaturation of the system.

The liquid in the stores can become contaminated e.g. by reason of the material (e.g. uranium) excavated in the mine or by the material used for mining (e.g. mercury for gold extraction). Contamination is thus present in a specific geological layer or passes through pollution of the groundwater or of other liquids (e.g. waters and surface waters) entering the system into this layer or it is present at least in the liquid (e.g. groundwater) located in the cavities.

Corresponding cavities which are used in accordance with the invention as stores are located in particular in mines in different groundwater reservoirs and/or they pass through a plurality of groundwater reservoirs. Groundwater reservoirs which are sometimes also defined as aquifers are water-carrying, natural layers or rock masses having cavities which are suitable for guiding groundwater. Groundwater reservoirs are mutually separated or delimited geologically by means of water-impermeable layers, the so-called aquifuges. In general, the construction or opening of the mine causes various aquifers to be penetrated which frequently are flooded artificially or naturally (with groundwater) e.g. after the mine has been shutdown. Flooding of the mine causes liquids (in this case e.g. groundwater) e.g. from uranium-contaminated geological layers to mix with liquids/water from uncontaminated layers which results in all of the liquid in the mine becoming polluted unnecessarily.

In order to prevent this uncontrolled mixing of the water and therefore to avoid more significant damage to the groundwater and thus to the surrounding ecosystem, the aforementioned cleaning stages, in which a cleaning process can be conducted for the contaminated liquid, are preferably interposed or provided at suitable locations. The uncontrolled mixing of the water can also be avoided by suitable structural separation measures. In this manner, impurities e.g. in the groundwater can be removed or at least greatly reduced, so that long-term damage to the ecosystem is prevented and the groundwater can be rendered useable again for people and nature.

In order to achieve this, the cleaning stage preferably has at least one filter device for cleaning the liquid, preferably at least in or between stores, particularly preferably at least in or between stores in contaminated layers. The filter device can be used to achieve an increased reduction of contamination which in turn has a positive effect upon the groundwater and the purity/purification thereof, as the quality of the groundwater can be increased considerably by reason of the removed or at least greatly reduced contamination.

For this purpose, the filter device can be connected on the one hand to the pumping device in a fluidic manner such that the liquid is cleaned during a pumping process of the pumping device, preferably that the liquid is cleaned as it is conducted through the lines. On the other hand, in addition or alternatively at least one store can be filled at least partially with a porous material which then forms the filter device. For this purpose, reference is also made to the water-storing and water-cleaning system in accordance with EP 2 058 441 A1, the subject matter of which can also be used in a comparable manner as a filter device in stores of the present invention.

The filter device can also comprise e.g.: at least one barrier layer, which is aligned substantially horizontally in the store, for the purpose of lengthening the seepage path of the liquid, wherein the barrier layer is provided with at least one passage for the fluid, and located above and below the barrier layer is porous material; and a collecting vessel for collecting cleaned liquid, which extends from the bottom of the store in a substantially vertical direction upwards. The water collecting vessel comprises at least below the lowermost barrier layer at least one opening, through which the liquid can flow or seep.

In a development of the last-named filter device, a pumping device can be disposed in the water collecting vessel. In this case, a line from the pumping device extends in a vertical direction upwards at least out of the collecting vessel (and thus consequently into the corresponding store). The cleaned liquid can thus be supplied once again to the cleaning circuit, in order to increase further the extent to which the liquid is cleaned. In a preferred embodiment, the aforementioned line extends additionally also out of the store itself. This conveniently ensures that, on the one hand, the liquid is returned to the cleaning circuit and that, on the other hand, the cleaned liquid is provided in other stores or to the outside environment.

Alternatively or in addition, in a development of the last-named filter device the collecting vessel can also be disposed in such a manner that it is disposed above a connection opening which leads to an underlying store, wherein the collecting vessel substantially surrounds the connection opening. Therefore, a second underlying cleaning device can be connected to or provided on the cleaning device, which increases the effectiveness of the cleaning stage. Moreover, by providing turbines in the connection opening, it is additionally possible to generate energy if the liquid is preferably optionally drained from the collecting vessel into the underlying store.

Furthermore, the cleaning stage can comprise at least one cleaning device for raising or lowering the pH value of the liquid. This cleaning device has preferably at least one chalk layer, through which and/or along which the liquid is guided for the purpose of changing the pH value. In this manner, it is possible to raise e.g. groundwater, which in some regions has a particularly low pH value (of ca. 2-3), to a desired level, particularly preferably to a neutral pH value range. However, it is also feasible for water or other liquids having any current pH value to be raised or lowered to a desired value which deviates from the current pH value. Therefore, the pH value of the liquid can also be adapted in addition to, or for the purpose of, cleaning it.

Furthermore, if a single store extends over at least one uncontaminated layer and one contaminated layer, an artificial barrier can be provided in the store extending over the layers, which extends preferably along an aquifuge which separates the contaminated layer from the uncontaminated layer. In this way, contaminated liquid can be reliably prevented from mixing unnecessarily with uncontaminated liquid, even if a store extends over a plurality of groundwater reservoirs. This also results in improved groundwater protection, in particular because uncontaminated groundwater does not come into contact unnecessarily with contaminated (ground or surface) water or other contaminated liquids. In one development, the barrier can also be provided with a through-opening, in the flow path of which there is disposed a turbine for generating electricity, and which can be closed by means of a stop valve.

The lines in general extend in a particularly preferred manner in a substantially vertical direction upwards out of the respective store into at least one store disposed above it and/or out of the mine. The phrase “out of the mine” means in particular that the stated line extends as far as the surface of the earth and optionally beyond it into the surrounding area and is thus preferably accessible from outside.

Further preferably, the geothermal device or the geothermal energy is the primary energy source, wherein, however, in addition further, in particular renewable, energy sources, such as e.g. a wind energy plant for wind energy, a solar energy plant for solar energy and/or a pump storage station for flow energy, and the like can additionally also be provided. This ensures a sufficient supply of energy to the underground liquid management system at all times, wherein this is provided by means of renewable energies, as a result of which the environment is not additionally polluted. The energy generated by the regenerative energy sources—but also each externally supplied energy—can be stored by storing the liquid in a store situated in a higher location and can be converted at any time into energy (e.g. electricity) by optionally draining the liquid into a store situated in a lower location by driving a turbine disposed in the flow path (pump storage station).

It is also possible for a store to be formed as a liquid supply or liquid reservoir, in which liquid is collected and provided, e.g. for provision for the operation of the mine itself or, if the liquid is water, as an industrial water or drinking water reservoir or even for renaturation of the system and the surrounding area thereof. It is thus possible that for the operation of the mine or after it has been shutdown, liquid (in particular groundwater and/or surface water) can be obtained from a dedicated source for provisioning in any form. This prevents natural resources of the environment, such as e.g. water from surrounding rivers or lakes, from being used, which serves to conserve the environment on account that there are no unnecessary interventions therein, and can also promote a renaturation of the mine, its surrounding area and the cleaned liquids. By virtue of the fact that the mine is self-sufficient, it is also no longer dependent upon a public water supply, which is of considerable importance in particular in areas with scarce water resources, extends the scope of application or is at least more attractive from an economic point of view.

In a particularly preferred manner, the liquid is water, preferably groundwater and/or surface water or water provided artificially for the purpose of flooding the mine. As already described above, it can be further used or reused in a variety of ways; e.g. for renaturation purposes, wherein this is promoted further by the reduction in contamination.

Preferably, separating walls or separating layers consisting of clay or clay rock are provided in the underground liquid management system at the location where contaminated liquids are present or flow through, in order to clean liquids which are contaminated in particular by radioactive substances. In this manner, an effective cleaning device is provided for liquids which are contaminated in particular by radioactive substances.

In accordance with a further aspect, the invention describes a waterworks for providing drinking water and industrial water which comprises the underground liquid management system as a water management system and also an output system for providing the water from the water management system.

A method for operating a liquid management system is also disclosed.

The invention will now be described with reference to exemplified embodiments which are illustrated in the Figures of the accompanying drawings, in which

FIG. 1 shows an underground liquid management system in accordance with a first exemplified embodiment,

FIG. 2 shows an underground liquid management system in accordance with a second exemplified embodiment,

FIG. 3 shows an underground liquid management system in accordance with a third exemplified embodiment,

FIG. 4 shows an underground liquid management system in accordance with a fourth exemplified embodiment,

FIG. 1 shows an underground liquid management system 1 in accordance with the present invention. The underground liquid management system 1 comprises a first store 2. This store 2 is formed by means of one or a plurality of cavities of a mine M. In accordance with the invention, a mine is understood to be all types of mines, pits and the like which comprise underground cavities, and all types of natural caverns or cavern systems.

Disposed above the first store 2 is at least one second store 3. This second store 3 can be a store which is additionally provided independently of the cavities of the mine; i.e., e.g. a store provided in the area surrounding the mine (above the (earth's) surface O). Preferably, the second store 3, along with the first store 2, are formed by cavities of the mine M. In this manner, it is possible to utilise already existing structures of a mine M in a simple and cost-effective manner for an underground liquid management system. However, the invention is not restricted to a specific number of stores and can comprise any number of stores; in particular depending on how many stores are provided in the mine M. However, in theory the number of stores can also be increased artificially, in that e.g. further shafts are provided or individual shafts are subdivided artificially into a plurality of sub-shafts. The number of stores can also be less than the stores provided in the mine M, in that stores which are not required are not integrated into the system.

Whereas in FIG. 1 the stores 2, 3 are disposed with their entire volume one above the other, it is also feasible for at least the bottom of the second store 3 to be disposed above the first store 2. In this case, the stores 2, 3 are thus disposed in a mutually offset manner in a horizontal direction one after the other. The only decisive aspect is that the stores are disposed in such a manner that a gravitation-induced flow of liquid can be effected from a higher level of a store 3 to a lower level into another store 2.

In accordance with the invention, the term “liquid” can be understood to refer to any liquid. Preferably, the liquid is water, wherein in this case it can be groundwater and/or surface water and/or water guided artificially into the mine. In this manner, a liquid management system 1 or a water management system is provided, by means of which groundwater, surface water, industrial water or drinking water can be stored and in particular also cleaned. This is, in turn, an important basis for particularly effective groundwater protection and for the improved possibility of effecting renaturation of the entire system, its surrounding area and the liquids (e.g. surface water or groundwater). It is also feasible for the liquid to be (any) liquid, which is stored in the mine after it has been shutdown, for the purposes of storage, cleaning, energy generation and/or energy storage. In the last-named case, the economic feasibility of an operation can also be maintained after closure of the mine M, in that the mine M is “converted” in a cost-effective and simple manner for the storage and provision of liquids, i.e., enjoys new and further use, whereas the liquid management system 1 can be used at the same time for generating energy by means of the liquid stored therein. If numerous stores are provided, the liquid management system 1 can also be used for various liquids at the same time, wherein the liquids, in turn, can be used independently of each other for the purposes of storage, cleaning, energy generation and/or energy storage, as explained hereinafter.

The underground liquid management system 1 also comprises a line 4, which connects the stores 2, 3, for the purpose of conducting a liquid located in the mine M. The liquid management system is not restricted to a specific number of lines 4, 26. For instance, individual stores can be connected to one or a plurality of lines 4. Furthermore, it is also possible for only individual stores, a plurality of stores or all of the stores to be interconnected (cf. FIG. 2 to FIG. 4). It is likewise feasible for individual stores, a plurality of stores or all of the stores to be connected to only one reservoir 4 (cf. FIG. 4). Alternatively or in addition, the line 26 can also extend out of the mine M, i.e., to the (earth's) surface O or beyond it to the outside environment of the mine M (cf. FIG. 2).

The lines 4, 26 are formed preferably as a rising pipe and can be formed either by means of a separately provided rising pipe 4, 26, which e.g. have already been provided during operation of the mine M, or by means of already existing or subsequently introduced connection shafts 5, 27 provided in the mine M. The lines 4, 26 extend upwards from the respective store 2 into at least one or a plurality of or even all of the stores 3 disposed thereabove and/or outwardly, i.e. to above the (earth's) surface O. This is described in greater detail in further exemplified embodiments. It should be noted that the invention is not restricted to the substantially vertical alignment of the lines 4, 26 shown in the Figures, as long as the lines 4, 26 permit the conveyance of liquid from a lower level towards a higher level.

In order to prevent an undesired back-flow of the liquid from a higher level, i.e., the second store 3 in FIG. 1, to a lower level, i.e., to the first store 2 in FIG. 1, via the line 4, 26, a vacuum valve 6 is provided preferably at the upper end of the line 4, 26 (or rather in the shaft 5, if the shaft is used as a line).

In order to guide the liquid through the line 4, a pumping device P is provided in the store 2, which is situated at a deeper location corresponding to the flow direction, by means of which pumping device the liquid is drawn in from the first store 2 and conveyed into the second store 3 via the line 4. For this purpose, the pump P is disposed preferably on the bottom of the first, deeper store 2, in order to permit the most effective possible conveyance of all of the liquid from the first store 2.

In accordance with the invention, in order to operate the pump P there is provided a geothermal device 7 which is illustrated only schematically in the Figures. Geothermal devices are well known and therefore shall not be described further at this juncture. The provision of a geothermal device is particularly advantageous since mines M extend generally to significant depths and the generation of geothermal energy (ground heat) is simple by reason of the low, additional drilling depth in comparison with the case where the geothermal energy must be generated starting from the earth's surface O. Therefore, in a simple manner and by means of regenerative energies, it is also possible to ensure operation of the pump P at all times in an environmentally sound manner and independently of external influences. Furthermore, the generated energy (electrical energy, heat, cooling energy) can be provided for other components inside or outside of the system and/or can be fed into an electricity network or a heating or cooling circuit or network or the like.

The geothermal energy can be used in addition for a thermal power station/heat pump which are not illustrated but are well known, wherein the heat energy can be used for the system itself or can be discharged from the system for external use. It is thus possible to use the generated thermal energy directly by discharging it in a known manner, and to use the thermal energy indirectly by converting it into electrical energy.

In addition to the heat pump, the geothermal device 7 can also be provided as an energy system for production both of heat and also cooling energy. For example, in the case of direct heat exchanger-ground heat systems, cooling energy is produced as a waste product in heat generation. In order also to render it accessible and use it, the installation of the geothermal device 7 can involve two deep drilling procedures, in which in each case a probe circulates. By reason of the geothermal heat, a liquid cooling medium evaporates therein, absorbs energy and travels by means of inherent pressure to a compressor. Consequently, as the heat is extracted the probe cools down. The cooling energy generated can then be used by a second circuit within the probe, wherein the cooling medium used is e.g. an ammonia mixture.

The heat and cooling energy generated or produced by the geothermal device 7 as a heat pump or energy system can be used, just like the generated electrical energy, for the (surrounding) industry, residential areas and the like or the mine M itself. The geothermal device 7 or the ground heat generated (upon conversion of the mine) can thus likewise be used as an energy supplier for electricity, heat and cooling energy, e.g. for sale to third parties or for the auxiliary power (e.g. of the active mine).

In addition to the geothermal device 7 as the primary energy source, it is also feasible for the system 1 to comprise further energy sources. In particular, all current and future regenerative energy sources can be used. These include in particular wind energy plants (not shown) for generating wind energy, solar energy plants (not shown) for generating solar energy, pump storage stations for generating flow energy or other known energy sources.

In particular, the pump storage station is particularly advantageous, as it can be integrated in space-saving and cost-saving manner in the underground liquid management system 1. For this purpose, already existing, vertical connection shafts 5 or other passages are preferably used between the stores 2, 3 which are preferably disposed one above the other. For this purpose, e.g. a turbine 8 or another comparable electricity generating device is provided therein for the purpose of generating electricity. By virtue of the fact that the liquid flows off from the second, higher store 3 into the first, deeper store 2 by reason of gravitational forces, the turbine 8 is driven and produces electricity. For this purpose, e.g. a generator 9 is also provided. The electricity can then be provided e.g. for the mine M or can be fed into an electricity network.

In order to regulate the flow rate of the liquid from the second store 3 to the first store 2, a closure device, e.g. a stop valve 10, is provided preferably in the flow path between the second store 3 and the water turbine 8. This stop valve 10 can be used preferably to regulate the flow rate of the liquid in a continuously variable manner. In the closed state, the second store 3 in a storage operation can thus be used as a store for providing the liquid which is conveyed by means of the pumping device P (driven at least by geothermal energy) from a lower level into the upper store 3. The stored liquid in the second store 3 can then be removed from the second store 3 e.g. for further use. Alternatively, the stored liquid can be used as required by optionally opening the stop valve 10 for the purpose of producing energy (electricity), in that the turbine 8 is driven as the liquid flows from the second store 3 to the first store 2.

It is also feasible for an additional store, not illustrated in the Figures, to be provided which is formed either likewise by cavities of the mine M or else is disposed in addition, e.g. above the (earth's) surface O. A store which is disposed in this manner can be formed as a liquid supply or liquid reservoir, in which liquid is collected and provided. This liquid supply can be provided for the operation of the mine M itself or even for any other purposes, e.g. for removal or else as a liquid reservoir or water reservoir for the surrounding population or agriculture or for renaturation purposes. The liquid reservoir can also be formed by one of the already previously described stores, preferably the store 3 located closest to the (earth's) surface O, in that in a particularly preferable manner the discharge to the further stores 2 is blocked or retarded (e.g. by means of the stop valve 10).

As already described, the cavities of the mine M which form the stores can extend over various groundwater reservoirs. It is conceivable that some stores extend in uncontaminated layers N and other stores extend in contaminated layers K. Contaminated layers K are located mostly at greater depths, in which extraction is operated in the mine M. Either the material extracted/to be extracted or a material used for extraction purposes in the mine M can cause e.g. the groundwater to become polluted, which leads to contamination of the groundwater and thus of the corresponding geological layer. This is illustrated by way of example in FIG. 2 which shows an underground liquid management system 20 in accordance with a second exemplified embodiment. In relation to the first exemplified embodiment, like features are designated by like reference numerals. In relation to all corresponding features, reference is made in full to the above statements relating to the first exemplified embodiment. It should also be noted that any combination of the features and embodiments of the exemplified embodiments together is possible within the scope of the invention.

FIG. 2 shows a mine M having four stores 21, 22, 23, 24 which are each disposed one above the other in a vertical direction. However, the invention is not restricted to a specific number of stores or their illustrated arrangement with respect to each other. On the contrary, any number of stores is feasible, wherein at least one store (or the bottom thereof) must be disposed above at least one other store (of the bottom thereof).

In accordance with the second exemplified embodiment, the two lower stores 21, 22 are disposed in a contaminated layer K.

The two upper stores are located in an uncontaminated layer N. However, it is also feasible e.g. for the uncontaminated layers N and contaminated layers K to be disposed differently or else also for one or a plurality of shafts or stores to extend over at least one or a plurality of geological layers, wherein at least one of the layers may be contaminated and at least one other one may be uncontaminated. The latter case will be explained in greater detail with reference to FIG. 3.

A separation between an uncontaminated layer N and a contaminated layer K, which extend mostly in water-carrying, natural layers (groundwater reservoirs or aquifers), is generally achieved in a natural manner by so-called aquifuges, i.e., water-impermeable layers, such as e.g. clays. In FIG. 2, an aquifuge A is illustrated by way of example and schematically by means of a broken line.

In accordance with the second exemplified embodiment, the two lower stores 21, 22 are connected to a line 4. Likewise, the two upper stores 23, 24 and the lowermost and uppermost stores 21, 24 are connected by means of lines 4. The uppermost store 24 is also connected by means of a further line 26 to the surface O or the outside environment. However, the invention is not restricted to this type of arrangement of the lines 4, 26. On the contrary, each store can be connected in any manner to each other store or the surface O by one or a plurality of lines 4, 26 which are/were already provided preferably by the mine operation.

The lines 4, 26, as also described in the first exemplified embodiment, are preferably each provided with a pumping device P for conducting a liquid; where expedient, a plurality of lines 4 can also be provided with a pump P. The pumping devices P are driven at least by means of geothermal energy by a geothermal device 7, optionally also in addition by means of other, preferably regenerative energy sources.

Provided between the stores 21, 22, 23, 24 are respective connection shafts 5 which preferably were also already provided when the mine M was opened. In at least one, a plurality of or all (see FIG. 2) of the shafts 5 it is possible to provide a stop valve 10 and a turbine 8—connected downstream in a fluidic manner—with a generator 9, by means of which energy can be generated.

In order to prevent uncontrolled mixing of the liquid, which is located in the stores 23, 24 in the uncontaminated layer N, with the liquid located in the stores 21, 22 in the contaminated layer K, and therefore to avoid greater damage to the groundwater and thus to the surrounding ecosystem, a filter device 25 is preferably also provided as a cleaning stage. As shown in FIG. 2, the filter device 25 is connected in a fluidic manner to the pumping device P. Preferably, the filter device 25 is disposed in at least one, a plurality of or all of the lines 4, 26, which connect the stores 21, 22, 23, 24, preferably downstream of the pumping device P such that as the liquid is conducted through the lines 4, 26 it is guided through the filter device 25 and is thus cleaned. It is also feasible that as an alternative or in addition to the pump storage station (i.e., stop valve 10, turbine 8, generator 9) the filter device 25 is disposed in a shaft (passage) 5, so that cleaning of the liquid takes place as it is drained or conducted from an upper store to a lower store, e.g. thus in the energy generating operation.

It is thus possible to separate the lower stores 21, 22 from the upper stores 23, 24 selectively in terms of systems engineering by closing the stop valve 10 between the particular stores 22, 23 which are disposed in the transition from the uncontaminated layer N and the contaminated layer K. In this manner, the groundwater in uncontaminated layers N is protected against unnecessary contamination, whereas at the same time the contamination in the contaminated layer can be reduced, in order thus to restore the area surrounding the mine to its natural original state, i.e., renaturation.

In the lower stores 21, 22 a closed cleaning circuit can then be provided, in order to clean the contaminated liquid located therein. As previously described, for this purpose the liquid is guided via the pump P and the line 4 from the lowermost store 21 into the store 22 located thereabove. In the course of this pumping or storing process, the liquid is cleaned by means of the filter device disposed in the line 4. The liquid guided into the store 22 and optionally stored can flow off into the lower store 21 in an energy generating operation by opening the stop valve 10 disposed between the two lower stores 21, 22. The turbine 8 disposed in the flow path of the liquid is influenced by the liquid of the upper store 22 flowing off. Pollutants, e.g. in the groundwater of the contaminated layer K, can thus be reduced or removed optionally in the course of a plurality of cleaning cycles, while at the same time energy can be generated and the cleaned liquid can then be provided. It is thus possible, by reducing the contamination of the groundwater entering into or located in the stores (e.g. over a plurality of cleaning cycles) to clean the groundwater located in the corresponding aquifer and therefore to convert the layer into a substantially uncontaminated layer.

In essence, a common aspect of all of the exemplified embodiments is that the stores can have a ventilation device, in order to equalise an air volume in a store by out-flowing or in-flowing liquid. This ventilation device can be a ventilation line (not illustrated) connected to the surrounding area above the (earth's) surface O and used for aeration and deaeration of the respective stores.

Until the liquid in the lower stores 21, 22 or the groundwater in the contaminated layer K has been cleaned, a closed circuit can likewise be provided in the two upper stores 23, 24 in the manner already described for the purpose of generating energy and storing liquid. The liquid can optionally also be cleaned in the upper stores 23, 24 with a filter device 25.

When the liquid in the lower cleaning circuit has been sufficiently cleaned, it can be conveyed via a further line 4, which is provided with a pump P, into one or a plurality of stores 22, 23, 24 disposed thereabove, where it is provided either as a pump store for generating energy or is kept available in one of the upper stores or a further store, not illustrated.

In some regions, in which the liquid management system in accordance with the invention is used, the groundwater surrounding and optionally entering into the mine M has a very low pH value of only ca. 2 to 3. It is thus also feasible that at a corresponding location, preferably in or between the stores 21, 22, 23, 24, the cleaning stage also has a cleaning device (not illustrated), by means of which the pH value of the liquid can be changed; depending on which pH value between 0 and 14 the liquid has and which desired pH value the liquid is to have, the pH value of the liquid can thus optionally be raised or lowered. The cleaning device can be constructed in such a manner that the liquid is guided in a purposeful manner through or along natural or artificially provided chalk layers or chalk-coated devices. As the liquid is conducted or guided past, the chalk (or another substance provided in the cleaning device) dissolves slowly into the liquid and leads to an increase/decrease in the pH value and preferably to neutralisation of the conducted liquid (e.g. the groundwater). The cleaning device can be formed e.g. in or with a previously described filter device 25. For example, the cleaning device can also be provided in a chalk-containing store (e.g. one of the stores 21, 22, 23, 24 in FIG. 2), wherein e.g. the walls of this store are provided in a natural or artificial manner with a chalk layer. The cleaning device can be provided in or between each arbitrary store and in each layer (contaminated; uncontaminated).

In a further development of the previously described cleaning device, it can additionally be equipped with a pH value sensor which measures the pH value in one or all of the stores. On the basis of the obtained measurement results and of the pH value to be adjusted, the liquid can then optionally be guided through the cleaning device, so that the pH value can be adjusted according to the individual requirements. It is feasible for the cleaning device to have a first part for raising the pH value and a second part for lowering the pH value. The liquid whose pH value is to be changed can then optionally not be guided at all or can be guided through the first or second part of the cleaning device, depending upon whether the pH value of the liquid is to be maintained, raised or lowered.

Provided in the uppermost store 24 is the line 26 which extends towards the surrounding area and extends preferably to above the (earth's) surface O. The line 26 has a pumping device P which is disposed optionally in the store 24 or outside the mine M, e.g. on the (earth's) surface O. For example, the line 26 can also be provided or optionally introduced through the shaft 27 which connects the uppermost store 24 to the surrounding area. This line 26 then serves, optionally in conjunction with the pumping device P and further connections, to channel the liquid from the store 24, which serves as a storage reservoir, as an output system S. The combination of liquid management system 20 and output system S thus forms a waterworks W. The liquid is then preferably water, such as e.g. groundwater or surface water or water guided artificially into the mine M. The liquid management system 20 can then be defined as a water management system. This type of waterworks W serves to provide drinking water or industrial water which can be channelled upon requirement from the liquid management system 20. Equally, the waterworks W effects renaturation of the surrounding area of the mine and of the liquid and also provides improved groundwater protection.

It should be noted that along with the uppermost store 24, in addition or alternatively each arbitrary store 21, 22, 23 can have a line 26 which extends to above the (earth's) surface O to the outside environment. Furthermore, the line 26 can also be provided with a filter device 25. Equally, the end of the line 26 protruding out of the mine M can be provided with a vacuum valve 6 or a connection for connecting a suction device or a collecting device or the like, in order to reliably capture liquid which has been output. The line 26 can also issue into a liquid reservoir, not illustrated.

FIG. 3 shows a third embodiment of an underground liquid management system 30. In relation to the aforementioned exemplified embodiments, like features are designated by like reference numerals. In relation to all corresponding features, reference is made in full to the above statements. It should also be noted that any combination of the features and embodiments of the exemplified embodiments together is possible within the scope of the invention.

In accordance with FIG. 3, the underground liquid management system 30 comprises three stores 31, 32, 33 formed from cavities of a mine M. This exemplified embodiment describes a case, in which (at least) one store 32 extends such that it protrudes from an uncontaminated layer N into a contaminated layer K; i.e., at least one store extends through a plurality of geological layers, wherein at least one of these layers is a contaminated layer.

In such a case, it is possible for all of the stores 31, 32 located in a contaminated layer K to be separated in a fluidic manner from stores 33 in uncontaminated layers N e.g. by closure of the uppermost stop valve 10 in the shaft 5. This produces a closed cleaning circuit for cleaning the liquid in these stores 31, 32, as has already been described previously. If the liquid is cleaned, it can be connected in any previously described manner to stores 33 in uncontaminated layers for energy generation, storage and optionally further cleaning of the liquid. The closed uppermost stop valve 10 can then optionally be opened.

However, in this case liquid from uncontaminated layers N if anything becomes mixed unnecessarily with contaminated liquid and is thus polluted. In accordance with the third exemplified embodiment, it is thus feasible to avoid uncontrolled mixing of the liquids by means of suitable structural separating measures and thus to provide effective groundwater protection. This is preferably achieved by providing an artificial barrier 35 in the store 32 extending over uncontaminated layers N and contaminated layers K, which barrier separates this store into a lower region 321 and an upper region 322. The barrier 35 is preferably disposed such that it extends along the aquifuge A which separates the contaminated layer K from the uncontaminated layer N. The barrier 35 consists preferably of a material which is at least impermeable to liquids. The barrier 35 is (sealingly) disposed in the store 32 such that no liquid can pass from the upper region 322 of the store 32, which is disposed in an uncontaminated layer N, to the lower region 321 of the store 32 which is disposed in a contaminated layer K (and vice versa). Therefore, the combination of the barrier 35 and the aquifuge A prevents any mixing of uncontaminated liquid and contaminated liquid in a more effective manner.

Furthermore, a passage 36 for optionally connecting the two regions 321, 322 of the store 32 can be provided in the barrier 35. The passage can optionally be closed preferably by a closure device, such as e.g. a stop valve 10. Furthermore, a turbine 8—connected in a fluidic manner downstream of the stop valve 10—with a generator 9 can be provided in the passage 36.

In order to avoid unnecessary contamination of the liquid in the upper stores or storage regions 33, 322, the stop valve 10 in the barrier 35 is closed during a cleaning process in the lower two stores or storage regions 31, 321 until the pollution in the liquid has been adequately removed.

As can be seen in FIG. 3, stores each located one above the other are connected by means of lines 4 and pumping devices P connected thereto. In the same manner, the two storage regions 321, 322 of the central store 32 are also connected together, wherein the line 37 connecting them in a fluidic manner extends preferably in a sealing manner through the barrier 35. Furthermore, a filter device 25 can be provided in the lines 4, 37 or even in another way (e.g. in the shafts 5 or the passage 36). At a desired location, a cleaning device, not illustrated, can likewise be provided for the purpose of changing the pH value of the liquid.

The pumping devices P are coupled to a geothermal device 7 in the manner described above.

As can also be seen in FIG. 3, the lowermost store 31 is connected to the overlying store 32 (specifically its lower region 321) by means of a line 4. It is also possible for at least the lowermost store 31 to be connected directly to the uppermost store 33 or a plurality of overlying stores or storage regions. To avoid unnecessary costs (e.g. for an additional pumping device), it is feasible for individual lines 4 to be connected together by connection line portions 4′. For this purpose, FIG. 3 shows by way of example that a line, which connects the lowermost store 31 to the lower region 321 of the central store 32, is connected by a connection line portion 4′ to a line 4 which connects the upper region 322 of the central store to the uppermost store 33. Preferably, valves 38 are provided in each case in the connection points of the lines 4, 4′. These valves 38 can be used optionally to regulate the liquid flow and optionally to determine the flow direction so as to avoid mixing of contaminated and uncontaminated liquid. Such connection line portions 4′ can be provided arbitrarily between all of the lines 4, 26, 37.

FIG. 4 shows a fourth embodiment of an underground liquid management system 40. In relation to the aforementioned exemplified embodiments, like features are designated by like reference numerals. In relation to all corresponding features, reference is made in full to the above statements. It should also be noted that any combination of the features and embodiments of the exemplified embodiments together is possible within the scope of the invention.

The underground liquid management system 40 in accordance with FIG. 4 corresponds substantially to that of FIG. 2. In FIG. 4, a store 41 is disposed in the contaminated layer, whereas the two overlying stores 42, 43 are provided in an uncontaminated layer.

The essential difference in the underground liquid management system 40 of the fourth embodiment resides in the configuration of the cleaning stage. In addition or as an alternative to the above-described filter devices 25 and cleaning devices which for the sake of simplicity are not illustrated in FIG. 4, the store can be filled at least partially with a porous material which then forms the filter device 44 for reducing contaminants in the liquid (e.g. surface water or groundwater) or the contaminated layer per se (e.g. over the liquid). This type of filter device is also described in a comparable manner in EP 2 058 441 A1. This will be illustrated by way of example hereinafter.

In FIG. 4, the store 41 located in the contaminated layer K is filled at least partially with a porous material 45. Within the scope of the present invention, the phrase “at least partially” is to be understood to mean that the store 41 is to be filled with at least as much porous material 45 as is required in order to store and clean the liquid in a sufficiently effective manner.

Preferably, the porous material 45 is rubble, gravel, sand (e.g. quartz sand) or a mixture thereof However, loam, silt and/or clay can also be used. Geotextiles can also be used. Other materials, such as e.g. synthetic materials, can also be used if, by reason of their porosity, the ratio of the volume of all of their cavities to their outer volume, they are able to store and transport water.

The filter device 44 comprises at least one barrier layer 46 or a plurality of barrier layers 46 (FIG. 4) which is/are disposed inside the store 41. The barrier layer 46 is also provided with at least one passage 47 for liquids.

Apart from the passage 47 which is permeable to water, the barrier layer 46 is produced from a material which is substantially impermeable to water. Within the scope of the present invention, the phrase “substantially impermeable to water” is understood to mean that the barrier layer 46 is formed in such a manner that the main part of the water which seeps through the store 41 is prevented from passing through the barrier layer 46 into the region above or below the barrier layer 46.

The barrier layer 46 serves to lengthen the seepage path (see arrows in FIG. 4) of the liquid to be cleaned through the porous material 45 of the store 41. By lengthening the seepage path, the liquid can be stored for longer periods inside the store 41. Moreover, the liquid is filtered over a longer period of time, which leads to an improved reduction in contamination and as a result of which the quality of the cleaned liquid is thus improved.

If the liquid reaches the barrier layer 46, then it begins to accumulate by reason of liquid seeping through subsequently. In this accumulated state, it enters into the capillaries of the porous material 46. As a result, in the region immediately upstream of the barrier layer 46, particles of muck and dirt become deposited or settle in a particularly effective manner in and on the pores.

Preferably, the barrier layer 46 is disposed horizontally, since when the barrier layer is disposed horizontally the seepage path of the liquid through the filter device 44 is at its longest, which has a particularly positive effect upon the quality of the filtrated water. However, any other inclination of the barrier layer 46 is possible if the characteristic of the barrier layer 46, namely to lengthen the seepage path of the liquid, is not lost as a result. The individual barrier layers 46 within a system can each have the same degree of inclination but can also be different in terms of their degree of inclination with respect to each other.

The passage 47 only takes up only a small amount of surface area relative to the entire barrier layer 46. Preferably, this constitutes a surface area of 5 to 20% in relation to the entire surface of the barrier layer 46.

Preferably, the passage 47 is disposed in the outer region of the barrier layer 46, so that the path travelled by the liquid along the barrier layer 46 corresponds approximately to the maximum possible, which produces a particularly good filtration result.

In the case of at least two barrier layers 46, as shown in FIG. 4, the passages 47 of each case two adjacent barrier layers 46 are preferably offset with respect to each other, particularly preferably they are disposed oppositely with respect to each other, so that the seepage path of the liquid is maximised.

Furthermore, the filter device comprises a collecting vessel 48 which extends from the bottom of the store 41 in a substantially vertical direction upwards, preferably to the top or just before the top of the store 41. It is also feasible for the collecting vessel to extend in the form of a well to the (earth's) surface O.

The collecting vessel 48 has, at least below the lowermost barrier layer 46, at least one opening 49, through which the cleaned liquid can flow or seep. The cleaned liquid can then be stored and provided in the collecting vessel 48; either for removal, for further cleaning and/or for generating energy.

There are different possible ways of removing the liquid from the collecting vessel 48, and the two preferred ways are described hereinafter.

In accordance with a first possible way, the filter device 44 preferably has a pumping device P inside the collecting vessel. The pumping device is preferably disposed at the bottom of the store 41. From this pumping device P, a line 4 extends upwards through the collecting vessel 48 and issues in an outlet 50, so that the upwardly conveyed liquid can be introduced into the store 41 or the filter device 44 for renewed cleaning above the uppermost barrier layer 46.

As illustrated in FIG. 4, it is also feasible for the line 4, which extends from the collecting vessel 48, to extend through all of the stores 41, 42, 43 and optionally to above the (earth's) surface, in order also to provide the liquid, preferable after cleaning has been effected, in the stores 42, 43 disposed thereabove or the surrounding area. At locations in the stores 41, 42, 43 required for this purpose, the line 4 comprises valves 38, from which output line portions 4″ branch off. By means of these valves 38, the liquid flow can be optionally regulated and the flow direction can be optionally determined so as to avoid mixing of contaminated and uncontaminated liquid. If the cleaning is completed, the valve 38 in the store 41 can be closed with respect to the corresponding output line portion 4″, so that the liquid is then guided by the line 4, which is open at the top, optionally into the stores 42, 43, which are connected by means of this line 4, or into the surrounding area.

It should be noted that all of the previously described lines 4 can be formed according to the line 4 which is illustrated in FIG. 4 and extends over all of the stores and optionally to the (earth's) surface O and is provided with corresponding valves 38 and output line portions 4″. In this simple manner, the number of lines 4, 26, 37 can be reduced, as only a small number of lines 4 has to be provided in order to connect a plurality of stores. It is also feasible that, above and beyond the exemplified embodiment illustrated in FIG. 4, a pump is provided in the line 4, which extends over all of the stores 41, 42, 43, within each store 41, 42, 43, so that only a single line 4 is required for operating a liquid management system 1, 20, 30, 40.

In accordance with a second possible way of removing the liquid from the collecting vessel 48, the collecting vessel 48 can be disposed in such a manner that it is disposed above a connection, e.g. a shaft 5 which leads to an underlying store (not illustrated), wherein the collecting vessel 48 preferably (substantially completely) surrounds the shaft 5. As already previously described, by means of a stop valve 10 the shaft 5 can be closed and optionally can be opened e.g. when the collecting vessel 48 is filled. The liquid can then be guided via the stop valve 10 and the shaft 5 into the store disposed therebelow. Preferably, an already previously described turbine 8 with a generator 9 is likewise disposed accordingly in the shaft 5.

The store which is disposed below the store 41 can likewise be equipped with a filter device 44, as illustrated in the lowermost store 41 of FIG. 4, so that the cleaning performance is improved.

Within the scope of the invention, in the case of liquids polluted with radioactive substances it is particularly advantageous if the stores (2, 3, 21, 22, 23, 24, 31, 32, 33, 41, 42, 43) or mines (M) are provided in clay rocks, as found e.g. in the Opalinus clay formation in the Jura region. This is particularly advantageous in particular in the case of uranium-contaminated mines. The clay minerals (e.g. kaolinite) contained in the clay serve to bond the radioactive substances which can thus be cleaned out of the liquid. In combination with the iron minerals which are contained in the clay rock and serve to reduce the radioactive substances and thus release them in the clay rock, the cleaning of liquids can be further improved in the underground liquid management system (1, 20, 30, 40).

It is additionally or alternatively possible for the walls of the stores (2, 3, 21, 22, 23, 24, 31, 32, 33, 41, 42, 43) or mines (M) to be provided with natural clay (in particular containing clay minerals) for the purpose of cleaning the liquid. For this purpose, a clay layer can be applied to the inner walls of the stores (2, 3, 21, 22, 23, 24, 31, 32, 33, 41, 42, 43), in particular if the mine (M) is not provided in clay rock. If the clay layer has adequately bonded radioactive substances or if it is saturated with radioactive substances, it can be removed and disposed of in an environmentally responsible manner, or stored or processed. If the mine (M) is provided in clay rock, e.g. the outermost clay layer of the inner walls of the stores (2, 3, 21, 22, 23, 24, 31, 32, 33, 41, 42, 43) can be removed at regular intervals and disposed of or processed accordingly, in order to remove the heavily contaminated clays layers and to continue cleaning with a “fresh” clay layer.

It is also feasible, by means of the use of clay to provide absorbing separating walls or separating layers (consisting of clay or clay rock) in the underground liquid management system (1, 20, 30, 40). For this purpose, the separating walls or separating layers formed from clay (rock) are provided preferably at locations in the mine (M) in or between the stores (2, 3, 21, 22, 23, 24, 31, 32, 33, 41, 42, 43) or even separately, e.g. thus outside the mine (M) where (contaminated) liquid is present or flows through; in a natural or artificial manner.

In relation to the exemplified embodiments, this means that separating walls or separating layers consisting of clay can be provided e.g. in the connection shafts 5, 27, the filter devices 25, the lines 4, 26, 37, the barrier 35, the passage 36 or at other suitable locations of the mine (M). For example, the barrier 35 or the filter device 25 can also be formed per se from a corresponding clay. It is likewise feasible to provide additional barrier layers consisting of clay as separating walls and a cleaning device, in particular for liquids polluted with radioactive substances.

It is also feasible to provide clay as a filter element, e.g. as loose clay particles, in the mine (M), so that it comes into contact with the contaminated liquid and can bond the radioactive substances contained therein. In other words, the clay does not have to be present as a layer or wall, but rather can be provided in any form, e.g. “fixed” (as clay slabs or clay chunks), “fixedly disposed” (as a separating layer or separating wall), “loosely disposed” (as filter particles in a (defined) filter housing) or “arbitrarily loose” (e.g. elutriated in the contaminated liquid). Preferably, the clay or clay rock is provided in such a manner that it can optionally be replaced or removed if a predetermined amount of contaminated (radioactive) substances is bonded therein. In this manner, an effective cleaning device is provided for liquids which are contaminated in particular with radioactive substances.

A method for operating a liquid management system 1, 20, 30, 40 will be described hereinafter.

The invention also includes a method for operating a liquid management system 1, 20, 30, 40 for mines M, comprising the step of pumping a liquid from at least one first store 2, 21, 22, 23, 31, 32, 41, 42, which is formed by a cavity of the mine M, into at least one second store 3, 22, 23, 24, 32, 33, 42, 43, the bottom of which is disposed above that of the first store 2, 21, 22, 23, 31, 32, 41, 42, via at least one line 4, which connects the stores 2, 3, 21, 22, 23, 24, 31, 32, 33, 41, 42, 43, for conducting the liquid, wherein the liquid is conveyed by means of at least one pumping device P through the lines 4 from the first store 2, 21, 22, 23, 31, 32, 41, 42 into the second store 3, 22, 23, 24, 32, 33, 42, 43, and wherein the pumping device P is driven by means of a geothermal device 7 of the liquid management system 1, 20, 30, 40.

The method also comprises the step of cleaning the liquid by means of a filter device 25, 44 of a cleaning stage, wherein either the filter device 25 is connected in a fluidic manner to the pumping device P or is disposed in a fluidic manner in a passage 5, which connects the stores 2, 3, 21, 22, 23, 24, 31, 32, 33, 41, 42, 43 such that the liquid is cleaned during the pumping process or as it is conducted through the passage 5, or wherein the filter device 44 is formed from a porous material 45 which fills the store 41 at least partially, and the liquid is cleaned as it is conducted through the porous material 45.

Furthermore, a passage 5 can be provided between the first store 2, 21, 22, 23, 31, 32, 41, 42 and the second store 3, 22, 23, 24, 32, 33, 42, 43, wherein the method in accordance with the invention can also comprise the steps of draining the liquid from the second store 3, 22, 23, 24, 32, 33, 42, 43 into the first store 2, 21, 22, 23, 31, 32, 41, 42 by optionally opening a stop valve 10 provided in the passage 5, and generating energy by driving an energy generating device 8 by means of the liquid drained via the passage 5, wherein the energy generating device 8 is disposed in the passage 5 downstream of the stop valve 10.

The invention is not restricted to the previously described exemplified embodiments. On the contrary, the features described therein can be combined in any manner.

The invention is also not restricted to a number of stores and also not to the number and type of configuration of the connection between the stores. For example, two or a plurality of stores can each be connected to one another by means of shafts and/or lines and corresponding pumping devices, turbines and stop valves. The stores also do not have to be disposed directly one above the other but rather can also be mutually offset in the horizontal direction and/or overlapping in the vertical direction, as long as a previously described fluidic connection is possible between at least some of the stores. Furthermore, any type and any number of cleaning stages (filter device; cleaning device) can be provided in each arbitrary store. Likewise, in addition to the geothermal energy any arbitrary energy source can be provided for operation of the system. Moreover, the geothermal energy can always be used both indirectly (electricity generation; cooling energy generation) and directly (heat generation). 

1. Underground liquid management system for mines for generating and/or storing energy, storing and/or cleaning liquids located in the mine (M), comprising: at least one first store which is formed by a cavity of the mine; at least one second store, of which the bottom is disposed above that of the first store; at least one line, which connects the stores, for conducting the liquid; at least one pumping device configured for conveying the liquid through the lines from the first store into the second store; and a geothermal device configured for at least operating the pump.
 2. Underground liquid management system as claimed in claim 1, wherein all of the stores are formed by of cavities of the mine.
 3. Underground liquid management system as claimed in claim 1, wherein cleaning stages are provided between and/or in the stores.
 4. Underground liquid management system as claimed in claim 3, wherein the cleaning stage comprises at least one filter device, configured for cleaning the liquid.
 5. Underground liquid management system as claimed in claim 4, wherein the filter device is connected in a fluidic manner to the pumping device such that the liquid is cleaned during a pumping process of the pumping device.
 6. Underground liquid management system as claimed in claim 4, wherein the store is filled at least partially with a porous material which forms the filter device.
 7. Underground liquid management system as claimed in claim 6, wherein the filter device further comprises: at least one substantially horizontally aligned barrier layer for lengthening the seepage path of the liquid, wherein the barrier layer is provided with at least one passage for the liquid, and porous material is located above and below the barrier layer; and a collecting vessel for collecting cleaned liquid, which extends from the bottom of the store in a vertical direction upwards, wherein the collecting vessel comprises, below the lowermost barrier layer (45), at least one opening, through which the liquid can flow or seep.
 8. Underground liquid management system as claimed in claim 7, wherein the pumping device is disposed in the collecting vessel, and a line extends in a vertical direction upwards out of the collecting vessel into the store, preferably also out of the store itself.
 9. Underground liquid management system as claimed in claim 7, wherein the collecting vessel is disposed in such a manner that it is disposed above a connection opening which leads to an underlying store, wherein the collecting vessel surrounds the connection opening.
 10. Underground liquid management system as claimed in claim 3, wherein the cleaning stage comprises at least one cleaning device for raising or lowering the pH value of the liquid.
 11. Underground liquid management system as claimed in claim 10, wherein the cleaning device comprises at least one chalk layer, through which and/or along which the liquid is guided for the purpose of changing the pH value.
 12. Underground liquid management system as claimed in claim 1, wherein, when a store extends over at least one uncontaminated layer and one contaminated layer, an artificial barrier is provided in the store which extends over the layers and extends preferably along an aquifuge which separates the contaminated layer from the uncontaminated layer.
 13. Underground liquid management system as claimed in claim 1, wherein the lines extend in a substantially vertical direction upwards out of the store into a store disposed above it or out of the mine.
 14. Underground liquid management system as claimed in claim 1, wherein the geothermal device is a primary energy source, and the system further comprises at least one further energy source.
 15. Underground liquid management system as claimed in claim 14, wherein the further energy source comprises a wind energy plant, a solar energy plant and/or a pump storage station.
 16. Underground liquid management system as claimed in claim 1, wherein a store is formed as a liquid supply, in which liquid is collected and provided.
 17. Underground liquid management system as claimed in claim 1, wherein the liquid is water, preferably groundwater and/or surface water or water guided artificially into the mine.
 18. Underground liquid management system as claimed in claim 1, wherein separating walls or separating layers consisting of clay or clay rock are provided in the underground liquid management system at the location where contaminated liquids are present or flow through, in order to clean liquids which are contaminated in particular with radioactive substances.
 19. Waterworks for providing drinking water and industrial water, comprising an underground liquid management system as claimed in claim 15 as a water management system, further comprising an output system for providing the water from the water management system.
 20. Method for operating a liquid management system for mines, comprising: pumping a liquid from at least one first store, which is formed by a cavity of the mine, into at least one second store, the bottom of which is disposed above that of the first store, via at least one line, which connects the stores, for conducting the liquid, wherein the liquid is conveyed by at least one pumping device through the lines from the first store into the second store, and wherein the pumping device is driven by a geothermal device of the liquid management system.
 21. Method as claimed in claim 20, further comprising: cleaning the liquid by a filter device of a cleaning stage, wherein either the filter device is connected in a fluidic manner to the pumping device or is disposed in a fluidic manner in a passage, which connects the stores, such that the liquid is cleaned during the pumping process or as it is conducted through the passage, or wherein the filter device is formed from a porous material which fills the store at least partially, and the liquid is cleaned as it is conducted through the porous material.
 22. Method as claimed in claim 20, wherein a passage is provided between the first store and the second store, wherein the method also comprises draining the liquid from the second store into the first store by opening a stop valve provided in the passage, and generating energy by driving an energy generating device by the liquid drained via the passage, wherein the energy generating device is disposed in the passage downstream of the stop valve.
 23. Method as claimed in claim 20, further comprising raising or lowering the pH value of the liquid, wherein the liquid is conducted through a cleaning device, comprising at least one chalk layer disposed in or between the stores. 